The present invention relates to a device for forwardly oriented case ejection in an externally driven automatic cannon, the device including a breechblock movable in a longitudinally displaceable manner by a continuously rotating control cylinder. The breechblock advances a means for supplying a cartridge to a chamber of the cannon. Empty cartridge cases are ejected from the cannon. For this supplying and ejecting process, an intermittently rotating rotor is provided having pockets which are adapted to receive the cartridges. The pockets are circumferentially disposed about the rotor.
Such an automatic cannon is disclosed in U.S. Pat. No. 4,612,843, wherein ejection levers are the means provided for ejecting the empty cartridge cases. The ejection levers extend on both sides of an outer region of the rotor into left and right laterally adjacent pockets of the rotor and are fixed to the breechblock. These ejection levers selectively eject the empty cases toward the front of the cannon from either the left rotor pocket or from the right rotor pocket depending on the direction from which the cartridges are supplied. A disadvantage of this arrangement is that the forces acting on the lever during ejection of the case are fully transferred by the lever arrangement directly to the breechblock, thereby subjecting the point of connection between the lever and the breechblock to an undesirable combination of torsonal and shearing stresses. In particular, this combination of stresses on these long levers, which are additionally bent at an angle in the region of the rotor pockets thereby incurring additional stress, can have a negative impact on the readiness of the breechblock.
In this arrangement, the ejection levers and the breechblock are made of one piece, requiring considerable expenditures for their manufacture. Additional stresses may occur at the points of connection thereof due to notch stress effects which may cause a premature breakdown of the entire breechblock. Moreover, in this prior art arrangement, in ejecting an empty case, it is necessary to guide the empty case longitudinally by means of an additional component, for example a pivotally movable partition wall. This requires an additional drive means to pivot this partition wall to the respective left or right ejector pocket of the rotor.